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Carbon Monoxide Deaths

The Following Information was kindly provided by the CORGI Trust

 

1                 ANALYSIS of DIDR Forms

 

1.1             Preliminary overview

 

There were 56 domestic incidents reported on DIDR forms that met the criteria for inclusion during the 12 month period (1st July 2008 to June 30^th 2009 inclusive). The main criteria are that either a definitive CO cause was established (usually through blood tests) or that the appliance was shown to be produce dangerous levels of carbon monoxide in the ‘as found’ condition.  Deliberate acts such as suicides are excluded.

 

All 56 involved use of mains natural gas.  No incidents were reported on the use of LPG; that is from refillable fuel tanks or cylinders. 

 

The incidents are usually notified directly to British Gas or CORGI Services both of whom provide an investigation service to a number of gas suppliers. Three of the 56 incidents were reported to HSE but had not been notified either to British Gas or CORGI Services.  Incident Co-ordinators from British Gas and CORGI Services liaise with each other to ensure any incident they become aware of is investigated and that the HSE is suitably advised that this will take place.  Possible duplicate reports are checked before being entered onto the database.

 

Of the 56 domestic incidents reported, 37 were fully reported. For the remaining 19 only short reports were received.  Thus, whilst for 56 cases the analysis covers incident date, casualty information and main appliance data (sub-sections 2.1, 2.2 and 2.6), for 37 of these the analysis additional covers incident installation appliances, flues, ventilation provision, appliance operation and servicing (sub-sections 2.3-2.13).

 

Each DIDR form is dedicated to a separate CO incident and will be referred to as such throughout the rest of this report. The incident rates and yearly trend data have been combined with the casualty details and are described within section 2.2.

 

Details of seven domestic natural gas incidents that occurred before July 1^st 2008 were received after last year’s analysis had been completed.  Four full reports and three short reports were received involving a total of 7 fatalities and 3 non-fatalities.  The details of these are presented in appendix C and the appropriate historical figures, charts and tables in the main body of the report have been updated accordingly.

 

 

1.2             Incident Details - Section 1 of DIDR

 

The number of domestic incidents, by month, involving fatal and non-fatal casualties between 1^st July 2008 and 30^th June 2009 inclusive are plotted in Figures 1 and 2 respectively.  The 12-month period commences on the 1^st July to reduce annual trends being skewed because CO incidents are higher in number in cold weather (as is evident from Figures 1 and 2).

 

Figure 1 Monthly incident numbers

 

 

Figure 2 Monthly casualty numbers

 

Figures 1 and 2 show that fatal and non‑fatal incidents showed a similar seasonal variation.

From the 1^st July 2008 to 30^th June 2009 there were 56 separate incidents classified as accidental CO poisoning. These were related to the use of natural gas in the home and affected 113 people, of whom 17 died.  At the time of writing, provisional estimates by the HSE for April 2008 to March 2009 had not been published, but after discussions with the HSE it was established that three fatal incidents had not been reported via DIDR forms.  These cases are listed in Table 1 and are included in the incident statistics in the main body of the report.

 

Table 1 Fatal incidents not reported on a DIDR form

                                         

Postal sector	Date of incident	Details	Source
TN6	18/1/2009	One male death	HSE
E10	20/4/2009	Elderly couple died	Press cutting; suspected boiler problem; falls within 2009/10 HSE reporting period.
TA6	24/9/2008	53 year old man	HSE still investigating; suspected cause cooker

 

1.3             Casualty Details - Section 2 of DIDR

 

A breakdown of those persons (96) reported to Downstream Gas as having been injured but not killed in CO incidents associated with the use of piped natural gas in the home during the reporting period 2008/09 is presented in Table 2 and in Figure 3, with the severity of the casualties classified into four groups. 

 

Table 2 Classification of non-fatalities

 

Table Notes:

The classifications N1 to N4, as used on the DIDR form, are:-

                N1 - requiring immediate hospitalisation for more than 24 hours

                N2 - requiring immediate hospitalisation for less than 24 hours, and/or hospital tests

                N3 - requiring other medical treatment (e.g. GP or Paramedic)

                N4 - receiving no medical treatment (e.g. treatment refused)

Figure 3 Reported Incident and casualty numbers

 

Last year there were no “casualties” categorised as N3 and N4.  This year a quarter of the casualties reported were classified as N3 or N4, which may suggest an increased reporting rate. 

 

Figure 3 shows the number of incidents and casualties that were notified during the 12 month reporting period. Using the data for the 12 months commencing on 1^st July 2008 and the estimated number of exposed people for December 2008, a corresponding incident, casualty and fatality rate has been determined (Table 3).

 

The risk values in Table 3 were calculated by dividing the number of incidents, casualties or deaths by the number of people at risk.  The exact number of people potentially at risk is open to interpretation.  It could be argued that anyone in the vicinity of a gas appliance is potentially at risk and so could include visitors from home or overseas as well as residents.  Including visitors would increase the number of people temporarily at risk.  Conversely, it could be argued that residents who have a gas appliance and who are visiting a home without a gas appliance are temporarily not at the risk or indeed overseas, decreasing the number of people at risk.  It was therefore concluded that for this report, the number of people at risk is taken to be the number of people that live in homes with at least one gas appliance (i.e. the number of households supplied with mains gas multiplied by the average number of people living in a household). 

 

The tabulated data above uses the following information:

a)     The number of households using mains natural gas for December 2008 is 22.9 million.  This was estimated from a projection of December 2007 (22.4 million) and March 2006 (21.6 million)[1] figures.

b)     The average number of people per household in Great Britain for mid 2008 is 2.42 [2] (the latest available figures).  As in previous reports this assumes the number of people per household with at least one gas appliance is the same as that for the whole population.

 

 

Table 3 CO incident numbers and rates for 1^st July 2008 to 30^th June 2009

 

 

The risk values for the 12 years previously reported are given in Table 4 and include the seven cases notified after the completion of the 2007/8 report. Yearly trends recorded in fatality and incident rates are also shown in Figures 4 and 5.  The trend is a moving average over three years centred on the middle year.

 

Table 4 Yearly data (July 1st to June 30th)

 

Reporting year	Number			Overall rate per million people per year
	Incidents	Fatalities	Casualties	Incidents	Fatalities	Casualties
96/97	75	21	176	1.63	0.46	3.83
97/98	93	24	198	2.04	0.53	4.35
98/99	108	24	237	2.30	0.51	5.05
99/00	69	23	147	1.52	0.51	3.24
00/01	85